Magnetic fluid filter

ABSTRACT

A magnetic fluid filter for filtering metallic particles from a fluid flow system. The filter comprises a magnetic array, a central support for the magnetic array, and arm pieces for positioning the effective range of the magnetic array in a fluid flow environment. The magnetic array includes a plurality of disc shaped magnets arranged with poles in opposition, interleaved with the arm pieces and disc shaped pole pieces.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/277,529 entitled “MAGNETIC FLUID FILTER” filed on Oct. 21, 2002,which is a continuation-in-part of U.S. patent application Ser. No.10/032,276 entitled “MAGNETIC FLUID FILTER” filed on Dec. 21, 2001. Thedisclosure of the above-described filed applications are herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a filter, and more particularly amagnetic filter for removing solid particles from a fluid.

2. Description of the Related Art

It is common practice to use fluids to lubricate moving parts ofmechanical systems. Foreign particles are often shed by the mechanicalsystem in operation into the lubricating fluid where it can cause wearand damage to the operating system and its components. Many mechanicalsystems already make use of primary filters to remove foreign particlesfrom the lubricating fluid of the system such as oil filter cartridgesin an automobile engine or transmission system.

The majority of contaminant particles in a mechanical system aremetallic in nature and therefore subject to magnetic attraction. Forthis reason, others have attempted to integrate magnets withconventional filters to provide removal of metallic particles. However,prior magnetic filters were typically limited in that their design wasspecific for a particular application environment. For example, themajority of current magnetic filters are limited to their application toengine oil filtration systems within automobiles. Moreover, such filtersare typically connected to the external flow path of the fluid to befiltered.

Accordingly, it would be advantageous for a magnetic filter to have thecapability of being integrated into any fluid system requiring filteringof metallic particles, and for the magnetic components in the filter tobe in closer proximity to the direct flow of the fluid through thefiltering device.

SUMMARY OF THE INVENTION

A filter apparatus comprises a magnetic array for removing metallicparticles from a fluid, the magnetic array comprising a plurality ofmagnets and a plurality of pole pieces, wherein the pole pieces areinterleaved between the magnets, a plurality of arm pieces extendingsubstantially radially from a center axis of the filter apparatus, andan assembly piece configured to support the magnets, pole pieces, andarm pieces.

In the filter apparatus, the plurality of magnets can be disc shaped,and the pole pieces can have a larger diameter than the magnets. Themagnetic array may comprise 3, 4, 5 or 6 magnets disposed a distanceapart from one another so that a polar repulsion force is maintainedbetween each magnet and its nearest neighbor magnet.

The arm pieces can be configured to reversibly mount the filterapparatus to the inside of a conventional oil filter, a filter cartridgeelement, a fluid reservoir, a transmission fluid flow line, or ahydraulic fluid flow line. The arm pieces may comprise a disc shapedcenter and a plurality of arms extending substantially radially from thedisc shaped center.

A fluid filter apparatus comprises a magnetic array, comprised of aplurality of magnets arranged in a like-pole to like-pole orientation,wherein the magnets are separated by a plurality of pole pieces. Thefluid filter apparatus further comprises a plurality of arm piecesextending substantially radially from a center axis of said magneticarray, and a support piece configured to support the magnetic array in afluid flow path such that fluid is allowed to flow over the magneticarray and pass within the effective magnetic range of the array in orderto extract ferrous contaminants from the fluid.

In the fluid filter apparatus, the fluid can be power steering fluid,and the center support piece can comprise a rod configured to supportthe magnetic array along a center axis. The rod may also be flexible soas to allow the filter to bend for insertion in a fluid flow path.

In the fluid filter apparatus, the pole pieces can have a largerdiameter than that of the magnets, and the arm pieces can have a discshaped center and a plurality of arms extending from the disc shapedcenter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional assembly view of one embodiment of amagnetic fluid filter.

FIG. 2 is a cross-sectional view of one embodiment of a magnetic filter.

FIG. 3 is an illustration of a magnet support piece before it is folded.

FIG. 4A is a perspective view of the magnet support piece of FIG. 3after a first fold is made.

FIG. 4B is a perspective view of the magnet support piece of FIG. 4after a second fold is made.

FIG. 5 is a cross section view of the magnetic filter of FIG. 2 takenalong the line 5-5.

FIG. 6A is a side view assembly stack illustration of a magnetic array.

FIG. 6B is a side view of the assembled magnetic array of FIG. 6A.

FIG. 7A is a cross sectional side view of an alternative embodiment ofthe magnetic filter.

FIG. 7B is a cut away view of a conventional automobile oil filter.

FIG. 7C is a vertical view of the alternative embodiment of theinvention of FIG. 7A.

FIG. 8 is a cut away view of the conventional oil filter of FIG. 7B withthe magnetic filter of FIG. 7A installed.

FIG. 9 is a cross-sectional assembly view of one embodiment of amagnetic filter.

FIG. 10 is a perspective assembly view of the magnetic filter of FIG. 9.

FIG. 11 is a perspective view of the magnetic filter of FIG. 9 in anassembled formation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the invention relate to a magnetic fluid filter forfiltering metallic particles from a fluid flow system. One example ofsuch a fluid flow system is a power steering unit in an automobile. Thisembodiment includes a cylindrical outer casing mated to two end piecesfor incorporating the filter into a fluid flow line.

Inside the magnetic fluid filter is an array of magnets that is held inplace by a support. In one embodiment, the magnetic array has aplurality of disc shaped magnets separated by “pole pieces”. Themagnets, each having a north pole and south pole, are arranged in alike-pole to like-pole configuration (north to north and south tosouth), and separated by the pole pieces. This configuration of magneticlike-poles creates a large magnetic gradient that attracts metallicparticles to the surface of the array.

As can be imagined, embodiments of the invention are not limited to thespecific magnetic array described above. For example, the magnetic arraycan include 3, 4, 5, 6 or more magnets disposed a distance apart fromone another so that a polar repulsion force is maintained between eachmagnet and its nearest neighbor magnet.

The magnet support can be made from a folded and punched piece ofnon-magnetic material, such as stainless steel. Notched or cut outsections within the support provide a nest for the magnetic arraycentrally along the length of the case such that fluid flowing throughthe case is within the effective range of the magnetic array. The polepieces can have a larger diameter than that of the magnets such that asfluid flows over the array the pole piece provides a shelter on thedownstream side of the pole piece for the magnetically attractedmetallic particles in the fluid. Alternatively, the pole pieces can havea smaller diameter than the magnets to provide a reservoir for themagnetically attracted metallic particles.

The arrangement of the magnets within the cylindrical case allows fluidflow in either direction. In addition to bi-directional fluid flow,because there is no device that can be filled or blocked, the filter canallow full flow of fluid at all times.

FIG. 1 is a cross-sectional assembly view of a magnetic fluid filter100. The filter 100 comprises a hollow cylindrical case 102 that ispreferably made of a non-magnetic material. The case 102 has twocircular open ends 104A, B into which a first and second hollow endpieces 106, 108 can be secured. The end pieces 106, 108 allow forinstallment of the filter 100 into any fluid line such that the endpieces 106, 108 provide secure attachment to the fluid flow system andan inlet and/or outlet whereby fluid is allowed to flow inside the case102 of the filter 100. The end pieces 106, 108 can be of a screwedconnection type, barb connection, or direct to hose swage connection, orany combination thereof.

The case 102 allows containment of fluid flow over a magnetic array 110that is disposed within the case 102. The magnetic array 110 includes aseries of magnets 112A-D arranged in a like-pole-to-like-polearrangement, whereby each magnet is separated by a pole piece 114A-C.The magnets 112 and pole pieces 114 are preferably disc shaped. Inaddition, the pole pieces 114 can vary in width, and in one embodimentare much more narrow than the magnets 112. The pole pieces 114 can bemanufactured from a magnetic material, such as iron or steel, and areslightly larger in diameter than the magnets 112A-D in order to provideshelter on the downstream side of the pole piece. The magnetic array 110will be discussed in further detail with respect to FIGS. 6A and 6B. Amagnet support 116 is also illustrated in FIG. 1, and is configured tosupport the magnetic array 110 within the case 102.

A cross-sectional view of the assembled magnetic filter 100 is shown inFIG. 2. The magnet support 116 is contained within the case 102 bycontacting the inner wall of the case 102, but allowing for end caps ormeans for secure attachment of the case 102 to a fluid flow system. Asshown, the assembled array 110 is supported within the case 102 by thesupport 116 extending the length of the case 102. Also shown in FIG. 2are the end pieces 106, 108 installed on the filter 100 to provide afluid inlet and outlet to the interior of the case 102.

As can be seen in FIG. 2, as fluid enters the filter 100 it flows overthe magnetic array 110 and through the case 102. Therefore, irrespectiveof the direction of fluid flow, metal particles will be filtered out ofthe fluid by the magnetic array 110. The filter 100 can therefore beinstalled in a fluid path irrespective of the direction of fluid flow.

Referring now to FIG. 3, in this embodiment the magnet support 116 iscomprised of a punched, and then folded flat piece of stainless steel orother non-magnetic material. The magnet support 116 is formed bypunching two voids 302, 304 in a flat piece of steel 307 so that when itis folded, it will have a length corresponding to that of the array 110,and a width corresponding to the diameter of the array 110 (See FIGS. 4and 5). A plurality of notches 310A-L, having a width corresponding tothe width of the pole piece 114, and a depth corresponding to thedifference in radius between that of the pole piece 114 and that of themagnet 112, are formed in the inner edges 314 of the magnet support 116.As can be imagined, the larger diameter pole pieces 114A-C can then bemounted inside of the notches 310A-L when the steel 307 is folded intothe proper formation. Of course, it should be realized that the magneticsupport is not limited to being formed from steel, and can be made fromany support material, magnetic or non-magnetic, such as metal orplastic.

Once the proper notches are formed in the steel 307, a first, rightangle fold is made along the longitudinal center-line of the punchedpiece of steel 116 so as to form corners 402, 404 on either end of thepunched piece 116 as indicated in FIGS. 4A, B. A second, 180° angle foldis then made along a center axis of the punched piece 116, perpendicularto the axis of the first fold, such that the two corners 402, 404 formedfrom the first fold are adjacent to one another.

Referring back to FIG. 3, when the magnet support 116 is folded to itsfinal geometry surrounding the magnetic array 110, the magnetic array110 is secured along four longitudinal inner edges 314 of the support onthe peripheral surfaces of the magnets 112A-D and pole piece 114A-C. Theouter surfaces of the magnets 112A-D and pole pieces 114A-C are then incontact with the inner edges 314 of the magnet support 116. When thefolded magnetic support 116 is placed within the case 102 (See FIGS. 2and 5), the magnetic disks 112A-D and pole pieces 114A-C are held inplace by the inward force placed on the support 116 from the case 102.

A cross-section of the magnetic array 110 supported in the case 102along line 5-5 is shown in FIG. 5. As can be seen in FIG. 5, the foldedmagnet support 116 forms an “X” shape along the cross section. Ofcourse, the magnet support 116 can be of any geometry, such as any framehaving a void corresponding to the shape and dimensions of the magneticarray 110 but not fully encapsulating the array 110, so as to supportthe array 110 in an effective position in the fluid flow path throughthe filter 100.

The magnetic array 110 will now be discussed in further detail withreference to FIGS. 6A and 6B. The like-pole-to-like-pole arrangement ofthe magnets 112A-D creates a magnified magnetic attraction at the areawhere the poles are held apart by the pole piece 114A-C. The designpresented by the magnetic array 110 increases the amount ofnon-homogeneous magnetic field produced by a fixed volume of magneticmaterial.

A magnetic field gradient is necessary to attract ferro-magnetic ormetal particles, and to hold them in the filter 100. The magneticattraction force provided by the magnetic field gradient should begreater than competing forces. In this case the competing forces areprovided by gravity and fluid flow through the filter 100, wherein evenif the fluid flow is great, the filtered particles are simply spreadalong the length of the array 110. One embodiment of the invention canobtain field gradients as high as 30 T/m close to the pole pieces 114A-Cin the array 110. An additional advantage to the array 110 is that itcan be more powerful than expensive rare earth magnets, and it is alsonot affected in performance by heat, as are rare earth magnets. Ofcourse, it will be appreciated that any type of magnet can be used inthe array 110.

FIG. 7A illustrates a cross sectional view of an alternative embodimentof a magnetic filter 700. The filter 700 comprises the magnetic array110 as described previously, however a sleeve 702 (of plastic, forexample) is disposed around the exterior of the array 110. As shown, thesleeve 702 has a plurality of elastic branches or spines 704 protrudingfrom its outer surface. The spines 704 are designed to be folded backalong the sleeve 702 such that the filter 700 can be slidably insertedinto the center return shaft of a conventional oil filter 706 (FIG. 7B).

FIG. 7C provides a top view of the filter 700 and its plurality ofprotruding spines 704 protruding from the sleeve 702. Alternatively, thespines 704 can be directly mounted or incorporated with the magneticfilter 700 along an outer surface of the case 702.

FIG. 8 is a cut-away side view of the filter 700 installed in theconventional oil filter 706. The spines 704 are configured to springoutward when installed in the oil filter 706 to hold the filter 700 inposition. As oil flows past the magnetic surface of the array 110 metalcontaminants are collected on the filter 700.

An additional embodiment of a magnetic filter 800 is illustrated in FIG.9, wherein FIG. 9 is a cross-sectional assembly view of the magneticfilter 800. Similar to the magnetic array 110, the magnetic filter 800comprises an array 801 of a series of magnets 802A-D having acylindrical shape, wherein the magnets 802A-D are arranged in alike-pole-to-like-pole configuration, and are separated by a pluralityof disc shaped pole pieces 804A-C, similar to pole pieces 114. In oneembodiment, the pole pieces 804A-C have a greater diameter than themagnets 802A-D, so as to provide shelter for contaminants collected onthe magnetic filter 800.

A plurality of arm pieces 806A-E are positioned in the array between themagnets 802A-D along with the pole pieces 804A-C, and at each end of thearray 801. The arm pieces 806A-E have disc shaped centers 807A-E withapproximately the same diameter as that of the magnets 802A-D, and aplurality of holding arms 808 extending radially outward from the discshaped centers 807A-E so as to hold the magnetic filter 800 in asubstantially fixed position when mounted into a fluid filter. The armpieces 806A-E extend in a substantially radial direction from a centeraxis 809 of the array 801, and at an angle θ of approximately 60° fromthe center axis 809 of the array 801 in one embodiment. Of course, theparticular angle of each arm, and number of arms can be changed withoutdeparting from the invention. The arm pieces 806A-E are illustrated inmore detail in the perspective views of FIGS. 10-11.

As shown in FIG. 9, the magnets 802A-D, pole pieces 804A-C, and armpieces 806A-E all have a circular void centered along the central axis809 of the array 801 so as to provide a hollow shaft along the length ofthe array 801 for accommodation of a center pin 810. The magnets 802A-Dhave central voids 820A-D, the pole pieces 804A-C have central voids822A-C, and the arm pieces 806A-E have central voids 824A-E. Duringassembly, the center pin 810 is slidably inserted into the hollow shaftprovided along the central axis of the array 801 so as to assemble themagnets 802A-D, pole pieces 804A-C, and arm pieces 806A-E. As the centerpin 810 is inserted, the arm piece 806A is positioned flush against anend piece 812 of the center pin 810. The end piece 812 is preferablydesigned to have a diameter larger than that of the hole in the armpiece 806A.

To complete the assembly of the magnetic filter 800, a removable endpiece 814 is fixed on the center pin 810 against the arm piece 806E soas to hold the array 801 on the center pin 810. The removable end piece814 can be, for example, a spring clip, a nut, a cotter pin, or anyother part, such that a holding force is provided between the removableend piece 814 and the end piece 812 to hold the magnets 802A-D, polepieces 804A-C, and arm pieces 806A-E in a substantially fixed position.In one embodiment, an end portion of the center pin may be threaded anda complimentary threaded fastener, such as a nut, can be fastened ontothe threaded center pin.

FIG. 10 is a perspective assembly view of the magnetic filter 800,wherein the orientation and angle θ at which the holding arms 808 of thearm pieces 806 extend from the center disc portion 807 can be seen moreclearly. An end portion 826 of the holding arms 808 preferably has agreater width than a stem portion 828 of the holding arms 808 so as toprovide a hooking, or grabbing point, for the holding arms 808 to attachto a housing or tubing when the magnetic filter 800 is mounted inside afluid filter. The arm pieces 806A-E are preferably made from a bendableor flexible material, such as a mild steel, such that the arm pieces806A-E are able to bend when the magnetic filter 800 is inserted into afluid flow environment. Of course, embodiments of the invention are notlimited to arm pieces that are made of any particular type of material.Nor should this embodiment of the invention be limited to holding armsof the described configuration. Other configurations of holding armssuch as those that do not have widened end portions are still within thescope of the invention.

As illustrated, during assembly, the center pin 810 is slidably engagedwithin the central orifices of each filter component. Accordingly, thecenter pin 810 is adapted to slide snugly through the central orifice824A of the arm piece 806A, then through the central orifice 820A of themagnet 802A. The center pin 810 is then slid through the central orifice824B of the arm piece 806B and through the central orifice 822A of thepole piece 804A. The center pin 810 is then slid through the centralorifices of the remaining parts until it reaches the removable end piece814.

FIG. 11 illustrates an assembled magnetic filter 800 wherein the centerpin 810 has been fully engaged within the central orifices of the armpieces, magnets, and pole pieces. The end piece 812 of the center pin810 is mated against the center portion 807A of the arm piece 806A. Ofcourse it should be realized that this specific configuration is not theonly configuration that is within the scope of the invention. Forexample, more or less number of arm pieces could be positioned withinthe filter. In addition, the arms themselves need not be on separatepieces, but could be mounted directly on the magnets or pole pieces solong as they provide a holding force for the filter when mounted withina fluid filter.

The magnetic filter 800 can be inserted into the case 102 of the filter100 to replace the array 110, or the magnetic filter 800 can beinstalled in a conventional oil filter in a similar fashion to themagnetic filter 700 (FIG. 8). Additionally, the magnetic filter 800 canbe installed in a transmission power steering fluid flow line, areplaceable filter cartridge element, a fluid reservoir, or a hydraulicssystem fluid flow line to attract and trap contaminant particles ontothe magnetic filter 800 from the fluids in the flow lines. In oneembodiment, the center pin 810 can be made of a flexible material suchthat the magnetic filter 800 can bend for easier insertion into a fluidflow line or adaptation to a curved fluid flow line, thus making themagnetic filter 800 more versatile with regard to applicationenvironments.

Although a preferred embodiment of the filter of the present inventionhas been discussed in the preceding section, the invention is notlimited to this embodiment. Other embodiments which capture the spiritof the invention are also anticipated. The scope of the invention is notlimited to the embodiments discussed above, but is only limited by thefollowing claims.

1. A magnetic filter apparatus comprising: a plurality of magnetsarranged in a like-pole to like-pole orientation; a plurality of polepieces, interleaved between said magnets, thereby creating a magnifiedmagnetic attraction adjacent said pole pieces; a plurality of armpieces, extending substantially radially from a center axis of saidfilter apparatus; and an assembly piece, configured to support saidplurality of magnets, said plurality of pole pieces, and said pluralityof arm pieces.